The spectroscopic identification of malignant tissues, termed “Optical Biopsy”, has been investigated for over two decades. Research has shown that native tissue fluorescence can identify malignant and pre-malignant tissues with high accuracy and in real-time. The real-time nature of fluorescence detection makes it an ideal technology for integration into image guided intervention systems, in which fluorescence will identify regions of cancerous and pre-cancerous tissues in real-time. This is normally followed by immediate treatment such as surgery, laser ablation or cauterization. The ability to detect cancerous tissues is of great benefit in a number of patient-care care areas, including breast cancer, skin cancer, ovarian cancer, gynecological cancer and choriocarcinoma. Treatment of digestive cancers such as esophageal, stomach, pancreas, liver, colon, rectal and anal would benefit from this technique. The treatment of urinary cancers such as kidney, bladder, testis and prostate would also benefit. These types of systems also benefit in the treatment of tumors such as carcinoid, nasophayngeal, retroperitoneal sarcomas, and soft tissue.
Among cancers affecting women in the U.S., breast cancer is the second leading cause of death. Standard screening methods such as mammography and ultrasound are ineffectual on younger women with dense breasts, and suffer from high false positive rates. Mammary ductoscopy was developed as a tool to enable physicians to visualize the milk ducts in women at high risk for developing breast cancer. However, ductoscopy also has a significant number of false positive indications when detecting cancer. Thus, there is a need for an improvement in the techniques for detecting cancerous materials when using microendoscopic detection techniques such as that used in mammary ductoscopy.
Most breast cancers start in the epithelial lining of the milk ducts or lobules. These are slow growing cancers which may exist for a long time, while remaining too small (<5 mm) to be detected by mammography, MRI or ultrasound. In an effort to detect small tumors, the ductoscopy technique was developed. In ductoscopy, the internal breast duct anatomy is visualized by endoscopy. In the procedure, the ducts are insufflated and a small diameter micro-endoscope (ductoscope) is inserted into the ducts. This procedure allows visual examination of the ducts as well as the ability to aspirate cells for cytology. However, the number of cells aspirated is small, and the effect of sampling errors on the accuracy of ductoscopy has not been evaluated. Ductoscope working channels are too narrow to allow biopsy samples to be taken during an examination. Ductoscopy is currently being used on patients with a high risk of developing breast cancer. The criteria include patients having each of the following, nipple discharge, having known breast cancer undergoing lumpectomy and patients having a high risk for developing cancer but having normal breast exams.
Various detection methods for certain types of cancer, such as breast cancer, involve the use of techniques such as ductoscopy. Ductoscopy, also referred to as mammary endoscopy, involves the insertion of a small fiber optic scope into the ductal openings of the nipple to look at the lining of the ductal system on a monitor or screen. This provides a window into the ductal system to help identify abnormalities. Often times, cells can be collected after the duct has been visualized with ductal lavage. The development of newer and more usable ductoscopes has enabled ductoscopy to be more easily performed in the operating room or the outpatient setting.
Ductoscopy is presently performed either during surgery or in an outpatient setting. Ductoscopy is often performed in the operating room as part of the surgical procedure to identify, remove and treat the cause of discharge from the breast. Typically, a numbing cream is applied to the nipple anywhere from thirty minutes to two hours prior to the procedure. The nipple is cleaned and made numb with a local anesthetic. By inserting the scope into the ductal orifice having the discharge, the clinician is able to see the abnormality causing the discharge and identify the best place to make a surgical incision to remove any papilloma. Ductoscopy may also be performed within an outpatient setting as it takes a relatively short period of time to perform and causes minimal discomfort.
Another manner for examining for potentially cancerous tissues is the use of ductal lavage to identify cancerous and precancerous cells in the milk ducts of the breast. The procedure can be done in a doctor's office and involves inserting a small catheter into the ductal opening of the nipple and washing out cells from inside the duct. The cells are analyzed by a pathologist who is trained to assess whether they are normal or have begun to look abnormal in ways that indicate they may be moving toward becoming cancerous.
Mammary ductoscopy was initially performed with pediatric endoscopes. Early ductoscopes had several drawbacks which limited their effectiveness. These limitations included the inability to insufflate ducts, the inability to cannulate smaller ductal openings, a lack of a channel to aspirate cells and poor image quality. Newer generations of micro-endoscopes are now available and FDA approved. Two approved commercial micro endoscopes are the VIaDuct® mammary ductoscopes from Acueity and the Mastascope® from Lifeline Biotechnologies. However, these units suffer from a number of limitations. Thus, there is a need for an improved manner of ductoscopy/endoscopy for tissue examination.